1. Field of Invention
This invention relates generally to a system and method for synchronizing the clock frequencies of power processing devices and digital signal processing devices in an electronic system.
2. Background of the Invention
Power amplifiers and power supplies based upon linear circuit technology have been traditionally inefficient and relatively heavy. Enormous heatsinks, fans, and other cooling methods are usually required to dissipate the power loss while having the undesirable effect of adding to the overall weight of a system.
In recent years, high frequency switching circuit technology, where the switching is based upon some clock with a predetermined frequency, has gained rapid and sophisticated development. Particularly, switching circuits have been developed to use pulse width modulation (PWM) to carry signals and deliver power. The design advantage of a PWM power supply is that small components can be used to rectify and smooth the high-frequency alternating current. The design advantage of a PWM amplifier is that the output devices in a PWM amplifier are unbiased and switch completely off at each half-wave cycle. One of the advantages is that these power supplies and amplifiers are inherently more efficient and run cooler than traditional linear circuit amplifiers and power supplies. A further advantage is that power processing with switching circuits can be accomplished with much less mass than traditional linear power processing circuits.
Electronic systems which employ power supplies and power amplifiers may also employ Digital Signal Processors (DSP) for various types of processing. These processors are also based upon some clock with a predetermined frequency. If the power supply and power amplifier are both pulse width modulated, a problem will likely exist if the Digital Signal Processor's clock is out of sync with the clock on any of the power processing devices. Namely, the difference or sum in clock frequency and/or clock synchronization may generate noticeable noise or induce a difference frequency. In the case of an audio system that employs PWM power processing and Digital Signal Processing, this may translate to audible tones.
Therefore, a need exists for a system and method for synchronizing the clocks of the power processing devices and digital signal processing devices in electronic systems.